The present invention relates to a cable connector having a composition wherein contacts are arrayed and held in a lateral alignment within a housing, a cable having one end connected to the contacts extending outside the housing.
Multiple pole cable connectors of the kind described above are commonly used at present: for example, cable connectors using flat cables are commonly used for connecting circuit boards, or the like. In recent years, a demand has emerged for cable connectors for high-frequency communications, connecting circuit boards contained in a personal computer, or connecting between a liquid crystal display panel and a processing unit, and as cable connectors for communications of this kind, cable connectors using AWG40 ultra-fine coaxial cables have been proposed. These coaxial cables have excellent high-speed transmission characteristics, and although provided with a shield layer, they are extremely thin, having a outer skin diameter of approximately 0.35 mm, as well as excellent durability with respect to bending. Therefore, it is thought that communications cable connectors using such cables will become widespread in the future.
However, this type of cable connector entails problems in that, since the cables have an ultra-fine coaxial wire structure, the material cost comprised in the cable is high, and moreover, since a sub-assembly process is required to peel off the cable covering into two stages, namely, the shield layer and the core wire, the wiring cost is also high, thereby making the overall cost of the cable connector expensive.
On the other hand, it is not uncommon to encounter a use situation where the electrical properties provided by coaxial cables are not required, but where properties equivalent to those of a cable connector using the aforementioned ultra-fine coaxial cables are required with regard to wiring space and bending tolerance. In other words, there is a demand for a compact, light-weight cable connector having excellent mechanical properties, which can be produced at low cost.
It is an object of the present invention to provide a cable connector, which is compact and light-weight and has excellent mechanical properties, similarly to a cable connector using ultra-fine coaxial cables, and which can be produced at low cost.
In order to achieve the aforementioned objects, in the present invention, a plurality of contacts (for example, female contact 20, plug contact 140) are arrayed and held in a lateral direction inside a housing, (for example, insulating housing 10, plug holding member 110) a cable is provided, the front end of which is connected to the contacts and the rear side of which extend externally from the housing, and shield covers (for example, a shield cover 30, upper cover 120 and lower cover 130) are provided on the housing, covering the outer side of the contacts. The cable is a FPC (Flexible Print Circuit) cable wherein a plurality of signal conducting layers are formed. This cable is fabricated by forming a plurality of signal conducting layers (for example, signal circuit layers 51) onto one surface of a sheet member (film member) made from an insulating material, and forming a ground conducting layer, (for example, ground circuit layer 53) onto the other surface thereof. The ground conducting layer is connected to the shield covers and the plurality of signal conducting layers are respectively connected to a corresponding one of the plurality of contacts.
In a cable connector of this kind, since a composition is adopted where an FPC cable is used as a cable for transmitting information to the respective contacts, it is possible to provide, at low cost, a cable connector which is compact and light-weight and has good bending durability, similarly to a case where ultra-fine coaxial cables are used. Since a ground conducting layer for connecting to the shield covers is provided in this FPC cable, it is possible to provide a cable connector having good electrical transmission properties compared to a flat cable, or the like, which does not have shield layer. If a multiple layer composition is used for the FPC cable and ground conducting layers are formed on either side of the signal conducting layers, then it is possible to obtain an FPC cable connector having electrical transmission properties equivalent to those obtained using a shielded cable.
Preferably, the ground conducting layer in the FPC cable is formed on the outer side of the housing from the electrical connecting section between the signal conducting layers and the contacts. By adopting a composition of this kind, no ground conducting layer is formed on the connecting section where the signal conducting layers are connected to the contacts, or on the rear face thereof, and hence the insulating properties between the signal conducting layers and the ground conducting layers can be improved. Moreover, since it is possible to prevent heat from escaping via the ground conducting layer when bonding the signal conducting layers using a heater tool, a cable connector with good bonding characteristics can be obtained.
For the. FPC cable in the vicinity of the connecting section between the signal conducting layers and the contacts, the flat end section may be used unaltered, but it may also be formed in such a manner that the plurality of signal conducting layers are respectively separated into individual band shapes (for example, see signal circuit connecting end sections 51a illustrated in the present embodiment.) If a composition of this kind, for example, a composition wherein a slit or a U-shaped cut is provided between the respective signal conducting layers is adopted, then even if there is some variation in the installation height of the contacts in the housing, or if they are inclined, then it is possible to make the respective connecting sections separated into band shapes correspond to the respective contacts. Moreover, even in cases where a housing structure is adopted having walls which provide separation between adjacently positioned contacts, it is possible to make the cable correspond accordingly.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.